Cathode construction



May 1, 1928.

A. N. LUCIAN CATHODE CONSTRUCTION Filed Feb. 6. 1926 INVENTOR ARSENE N.x UCIAN Patented May 1, 1 928.

ABSENE N. LUCIAN, OF PHILADELPHIA, PENNSYLVANIA.

GATHODE CONSTRUCTION.

Application filed February This invention relates to cathodes for use intriodes and the like. The object of the invention is to provide a hollow thimble shaped cathode capable of cooperating with the glass seals of a bulb or tube to complete a vacuous enclosurewithout unduly heating the glass seal.

The above and further objects of the invention will better be understood by reference to the illustrative embodiments of the invention described in the following specification in connection with the accompanying drawings which form a part hereof. These illustrative embodiments should be referred to however solely for illustration and not limitation.

In the drawings,

purposes of Fig. 1 is a vertical cross-section of a 7 preferred embodiment of the invention; and

Fig. 2 is a similar'view of a modification.

The thermionically functioning ortion of cathode proper C is formed pre erably of suitable metal, such as Monel metal in the shape of a hollow thimble, externally rovided with a series of grooves 1 in w ich may be embedded electron emitting material 2. A glam sealing portion B is provided which terminates in a uniform flange 4 occupying a plane substantially at right angles to the axis of the ortion C and 1s particularly well adapted both as to metal and physical formation for the fabrication of the s, 1926. Serial No. 88,888.

glass seal or pit 5 between the sealing portion B and glass envelope 3. The preferred metal for the construction of this hollow 3.5 portion B is a suitable alloy of nickel steel such as nickel 60% steel 40%, and its edge I or terminus rim 6 opposite to the sealing edge 4 is preferably as indicated in the drawings and is substantially the same in 40 cross-section as the main portion C. Interposed between the main portion C and its portion B is an intermediate heat resisting or insulating portion 7 which may be cylindrical as shown in Fig. 1, if it is fabricated of metal, low in its heat conductivity, such as nichrome or nickel steel, or which ma preferably be fluted or corrugated with the formation 8 shown for this similar portion in Fig. 2. The referred means of attaching this interme iate portion to the end portion C and B is by means of welds 9 and 10, or by simply soldering with a high temperature solder.

The inventive thought may have a variety of expressions as is contem lated in what I claim and desire to secure li y United States Letters Patent as follows:

A cathode for vacuum tubes comprising a thimble shaped tip of metal having a substantially cylindrical portion; an outwardly flared glass-sealing flange; and an intermediate portion of low heat conductivity.

ARSENE N. LUCIAN; 

